His first flight was made on August 14 1901 in Connecticut when he flew his Number 21 three times as reported by Bridgeport Herald, the New York Herald and the Boston Transcript . The longest flight was 60 meters (200 feet) above ground and lasted for 2.5 kilometers (1.5 miles) and that is significantly better than the short jump the Wright brothers did two years and four months later.
There are witness reports thet he flew about a kilometer (half a mile) as early as 1899. In January 1902 he flew 10 kilometers (seven miles) over the Long Island strait in the improved Number 22.
The reason his flights are so little known has been attributed to that he was of German origin and that the Wright brothers donated their Wright flyer to the Smithsonian Institute on the condition that the institute would not recognize an earlier aeroplane.
Both Number 21 and Number 22 were monoplanes, the first powered by a 20 hp engine and the later with a 40 hp engine. They used a system where the engine drove the front wheels up to take-off speed and then the power was switched to drive the propeller. This meant that he didn't have to use a catapult like Wright did.
The roll was controlled by the pilot shifing his weight, much like on a glider, the pitch was controlled by a tail wing and the yaw was controlled by altering the ammount of thrust on either of the two propellers.
In 1985 some US enthusiasts started building a replica of Whitehead's machine on December 29, 1986 Andrew Kosch made 20 flights, reaching a maximum distance of 100 meters (330 feet). On February 18, 1998 a German replica flew distances up to 500 meters.
The Wright brothers also visited Whitehead to discuss the purchase of one of his engines and they exchanged ideas and discoveries regarding flight.